1. Field of the Invention
This invention relates to triiodized N-methyldicarboxylic acid anilides and to processes for their preparation and use.
2. Description of the Prior Art
Compounds suitable for use as radiopaque agents, especially for intravenous uro-, angio- and cholegraphy, must meet very high requirements with respect to vascular system compatibility and pharmacological inertness. The triiodated benzoic acids used for uro- and angiography show a considerable osmotic pressure raised by the diagnostically necessary high salt concentration of the injection solutions. Therefore it was already tried to lower the osmotic pressure with retaining the same iodine concentration by linkage of two molecules. However, on the synthesis of these compounds considerable difficulties araised, which, for instance, resulted in low yields, e.g., U.S. Pat. No. 3,542,861.